1. Field of the Invention
This invention is directed to the extraction of valuable by-products from cocoa hulls.
2. Description of Related Art
Cocoa hulls are a waste by-product of the roasting of cocoa beans and have little value in chocolate manufacturing. Generally, the cocoa hulls are used as compost.
Seventeen Herrania and 22 Theobroma species have been described. See Schultes, R. E., J. Arnold Arb., 39:216, 1958; Cuatrescasas J., Cont. Nat. Herb. (USA), 35:379, 1964; and Wood, G. A. R. and R. A. Lass, Cocoa, 4th edn., Longman Inc., New York, 1985, pp. 11-37. Of these, Theobroma cacao is the only species of major economic importance because its fat rich seeds are the unique source of cocoa solids and cocoa butter used by the confectionery industry. Cocoa beans are produced by cocoa trees which are found in warm, moist climates in areas about 20 degrees latitude north and south of the Equator. In general, the seeds of the Theohroma cacao (of the order Sterculiacae) are known chiefly in two varieties: Criollo and Forastero, with Forastero divided into several varieties. A third group, called Trinitario, is essentially a cross between Criollo and Forastero and is not found in the wild. Criollo beans are pale brown in color while Forastero beans are a purple hue. The cocoa tree produces leaves, flowers and fruit throughout the year, and the ripe fruit or pod resembles a long cantaloupe, typically containing from about 20 to 40 almond-shaped cocoa beans.
The cocoa bean is comprised of an inner nib portion covered by an outer shell, also referred to as the hull. On a dry basis, the shell of the bean comprises about 12 to 15% of the weight of the bean, while the nib and residual moisture amounts to approximately 85 to 88%. Typical analytical data ranges for chemical components of cocoa nib are: fat content of 48 to 57%; theobromine content of 0.8 to 1.3%; caffeine content of 0.1 to 0.7%; total nitrogen content of 2.2 to 2.5%; ash content of 2.6 to 4.2%; and water content of 2.3 to 3.2% (see Pearson""s Composition and Analysis of Foods, 9th Edition, 1991).
Various processes are traditionally employed to extract cocoa butter and cocoa solids from commercial cocoa beans. Typical methods of processing cocoa beans include the steps of (a) bean cleaning; (b) bean roasting; (c) bean winnowing; (d) nib grinding; (e) liquor pressing to produce cocoa butter and cocoa cake, also referred to as partially defatted cocoa solids; (f) optionally cake alkalizing; and (d) cake milling.
The initial step of typical cocoa bean processing methods consists of cleaning the beans to remove extraneous non-cocoa materials. Conventional bean cleaning separates beans from extraneous non-cocoa materials by either size or density using a cleaning machine which is a gravity, vibratory or aspiration table (See Chocolate, Cocoa and Confectionery: Science and Technology, 3rd Ed., by Bernard W. Minifie, page 35; Chocolate Production and Use, 3rd Ed., by L. Russell Cook, page 144-146; and Industrial Chocolate Manufacture and Use, 2nd Ed., by S. T. Beckett, page 55.
In most conventional processes, roasting of the whole bean or nib is an essential step in the manufacture of chocolate or cocoa. Roasting develops the natural flavor and aroma of the cocoa beans, and also loosens the shell so that it can be readily removed during the winnowing process. The degree of cocoa roast is a time/temperature dependent relationship, where the time can vary from 5 to 120 minutes and the temperature of the whole bean can typically vary from 125xc2x0 C., and with respect to the roasting of nibs, an initial drying process step can be at just below 100xc2x0 C. to remove the shell, with second stage roasting of nibs alone being at elevated temperatures up to about 130xc2x0 C.; all of which depend on the construction of the machine, size of the batch and final product desired (see Chocolate, Cocoa and Confectionery: Science and Technology, 3rd Ed., by Bernard W. Minifie, especially page 37, 45-46; Chocolate Production and Use. 3rd Ed., by L. Russell Cook, page 146-152; and Industrial Chocolate Manufacture and Use, 2rd Ed., by S. T. Beckett, page 55-64) hereby incorporated by reference). U.S. Pat. No. 5,252,349 to Carter, Jr., hereby incorporated by reference), involves heating the bean to a temperature of about 152xc2x0 C. to 160xc2x0 C. for about 5 to 8 minutes.
An alternative method for directly processing cocoa beans to cocoa butter and partially defatted cocoa solids is disclosed in U.S. Pat. No. 6,015,913 (issued Jan. 18, 2000 to Kealey et al.), the disclosure of which is incorporated herein by reference. The method involves heating the cocoa beans for a time and at an internal bean temperature sufficient to loosen the cocoa shell without roasting the nib, winnowing the nibs from said shells, and screw pressing the nibs to produce cocoa butter and partially defatted cocoa solids. Typically, the internal bean temperature is about 100-110xc2x0 C., preferably less than about 105xc2x0 C. and typically, the heating is carried out by infra red heating in a micronizer. The winnowing is carried out in an air fluidized bed density separator. The loss of cocoa polyphenols including cocoa procyanidins is minimized because the temperatures used are lower than those used in a process.
The winnowing operation serves to separate the beans into the desired inner portion of the bean (nib) and the outer portion of the bean (shell or hull). The principle of separation by a winnowing process depends on the difference in the apparent density of the nib and of the shell. Standard winnowing machines make use of the combined action of sieving and air aspiration. As discussed earlier, the shell is loosened during the conventional roasting step and/or other heating or drying steps. After loosening, the beans are typically broken between rollers or such devices to shatter the cocoa beans along natural fracture lines of the cocoa nib to facilitate shell removal during winnowing (see U.S. Pat. No. 2,417,078 to Jones. U.S. Pat. No. 5,252,349 to Carter, Jr., hereby incorporated by reference. Chocolate, Cocoa and Confectionery: Science and Technology, 3rd Ed., by Bernard W. Minifie. pp. 47-51; Chocolate Production and Use, 3rd Ed., by L. Russell Cook. pp. 152-153; and Industrial Chocolate Manufacture and Use, 2nd Ed., by S. T. Beckett, page 67-68.
Some cocoa bean processing techniques include the use of thermal pre-treatment equipment to aid in the separation of the shell from the nib. This involves giving the beans a thermal shock by hot air, steam or infra-red heat (see U.S. Pat. No. 4,322,444 to Zuilichem et al., and British Patent No. 1,379,116 to Newton, Chocolate, Cocoa and Confectionery: Science and Technology, 3rd Ed., by Bernard W. Minifie page 44-45; Chocolate Production and Use. 3rd Ed., by L. Russell Cook, page 155; and Industrial chocolate Manufacture and Use, 2nd Ed,. by S. T. Beckett, page 60-62, hereby incorporated by reference).
Infra-red pre-treatment uses infra-red heating to rapidly heat and expand the beans which assists in loosening the shells. The method consists of treating the beans with infra-red radiation for a period between one-half and two minutes, during which time the beans are typically heated to a temperature of about 100 to 110xc2x0 C. The infra-red radiation used has a wavelength between 2 and 6 microns which corresponds to a frequency in the range of 0.7 to 1.2xc3x97108 megacycles per second. This energy penetrates and excites the molecules of the bean which causes them to vibrate at their own frequency and results in rapid heating of the beans.
Cocoa hulls resulting from the above processes are removed from further cocoa/chocolate manufacturing steps. As such, the cocoa hulls are considered a waste by-product with little economic value, although they are used for mulching or composting applications.
As used herein, the term xe2x80x9cphytosterolsxe2x80x9d refers to lipid mixtures obtained from a plant source containing free or bound sterols. A cocoa oil which contains phytosterols is prepared by extracting cocoa hulls with a solvent for the phytosterols. The phytosterols are a mixture of free and bound sterols, with the free sterols being up to about 90% of the phytosterols present. The phytosterols include campesterol, xcex2-sitosterol, stigmasterol, cycloartanol, 24-methylene cycloartenol, as well as minor amounts of other phytosterols. The bound phytoserols include the fatty acid ester or ferulate derivatives of the phytosterols. The cocoa oil can further comprise tocopherols and tocotrienols which are members of the tocol family.
The process for extracting the cocoa oil comprises the steps of: a) grinding the cocoa hulls; b) extracting the ground cocoa hulls with a solvent for the phytosterols; c) removing the solvent; and d) recovering the cocoa hull oil.
The phytosterol-containing cocoa oil can be included in foods, dietary supplements, pharmaceuticals, and cosmetics.
Cocoa beans can be divided into four categories based on their color: predominately brown (fully fermented), purple/brown, purple, and slaty (unfermented). Preferably, as indicated above, the cocoa oil is prepared from underfermented cocoa beans which have a higher cocoa phytosterol content than fermented beans. Underfermented beans include slaty cocoa beans, purple cocoa beans, mixtures of slaty and purple cocoa beans, mixtures of purple and brown cocoa beans, or mixture of slaty, purple, and brown cocoa beans. More preferably, the cocoa beans are slaty and/or purple beans. Underfermented beans typically have a fermentation factor of 275 or less.
The xe2x80x9cfermentation factorxe2x80x9d is determined using a grading system for characterizing the fermentation of the cocoa beans. Slaty is designated 1, purple is 2, purple/brown is 3, and brown is 4. The percentage of beans falling within each category is multiplied by the weighted number. Thus, the xe2x80x9cfermentation factorxe2x80x9d for a sample of 100% brown beans would be 100xc3x974 or 400, whereas for a 100% sample of purple beans it would be 100xc3x972 or 200. A sample of 50% slaty beans and 50% purple beans would have a fermentation factor of 150 (50xc3x971)+(50xc3x972).
The preferred solvents are petroleum ether, hexane, pentane, and ethyl ether. The solvent is recovered by vacuum distillation or other conventional methods.
The phytosterols may be purified by preparative high pressure liquid chromatography or column chromatography.
The cocoa oil, particularly the purified cocoa oil, may be useful in foods, as a food additive, in a dietary supplement, or in a pharmaceutical. The cocoa oil may be used with a carrier, a diluent, or an excepient. The carrier, diluent, or excepient selected will depend on the particular end use, for example, for human or veterinary use, whether as a food, food additive, or dietary supplement or in a pharmaceutical.
As used herein a xe2x80x9cfoodxe2x80x9d is a material consisting essentially of protein, carbohydrate and/or fat, which is used in the body of an organism to sustain growth, repair and vital processes and to furnish energy. Foods may also contain supplementary substances such as minerals, vitamins and condiments. See Merriam-Webster""s Collegiate Dictionary, 10th Edition, 1993. The term food includes a beverage adapted for human or animal consumption. As used herein a xe2x80x9cfood additivexe2x80x9d is as defined by the FDA in 21 C.F.R. 170.3(e)(1) and includes direct and indirect additives. As used herein, a xe2x80x9cpharmaceuticalxe2x80x9d is a medicinal drug. See Merriam-Webster""s Collegiate Dictionary, 10th Edition, 1993. A pharmaceutical may also be referred to as a medicament. As used herein, a xe2x80x9cdietary supplementxe2x80x9d is a product (other than tobacco) that is intended to supplement the diet that bears or contains one or more of the following dietary ingredients: a vitamin, a mineral, an herb or other botanical, an amino acid, a dietary substance for use by man to supplement the diet by increasing the total daily intake, or a concentrate, metabolite, constituent, extract or combination of these ingredients.
The cocoa oil, particularly the purified cocoa oil, may be used in cosmetics. The cosmetics are formulated using conventional methods known in the art. Typical cosmetics include creams, lotions, gels, conditioners, shampoos, soaps. dyes, and other compositions for external use. The cocoa oils may be used with other conventional cosmetically acceptable ingredients such as moisturizers (e.g., cetyl alcohol, dimethicone silicon, isopropyl lanolate, myrisate, or palmitate, lanolin and lanolin alcohols and oils, octyl dodecanol, oleic acid, panthenol, stearic acid, and stearyl alcohol), preservatives (e.g., trisodium and tetrasodium edetate and tocopherol), antioxidants such as vitamins, antimicrobials (e.g., butyl, propyl, ethyl, and methyl parabens, DMDM hydantoin, methylisothiazolinone, phenoxyethanol, and quaternium-15), thickeners (e.g., candelilla, carnuba, and microcrystalline waxes and carbomer and polyethylene thickeness), solvents (e.g., butylene glycol and propylene glycol, cyclomethicone, ethanol, glycerin), emulsifiers (e.g., glyceryl monostearate and lauramide DEA, and polysorbates). color additives such as synthetic organic colors derived from coal and petroleum sources (e.g., DandC Red No. 7 Calcium Lakes) and inorganic pigments (e.g iron oxides and mica), hair dyes such as phenol derivatives (e.g., aminophenols), pH adjusters (e.g., ammonium hydroxide, citric acid, and triethanolamine), and other FDA approved ingredients such as magnesium aluminum silicate, silica, and talc (absorbents), sodium lauryl sulfate (a detergent), stearic acid (a cleansing emulsifier), and zinc stearate (a lubricant).
Sterols, particularly phytosterols, can be used in a variety of products including pharmaceuticals, cosmetics, vitamins, foods, and dietary supplements. The ferulated polysterols are particularly useful as antioxidants.
The sterol amounts reported in the following examples were determined using the analytical procedure described in Rogers et al., xe2x80x9cIdentification and Quantitation of gamma-Oryzanol Components and Simultaneous Assessment of Tocols in Rice Bran Oilxe2x80x9d, J. Amer. Oil Chem. Soc. 70(30) 1993 and Carpenter, et al., xe2x80x9cLipid Composition of Herrania and Theobroma Seeds, J. Amer. Oil Chem. Soc. 71(8) 1994.